1. Field of the Invention
This invention relates to door bolting and opening mechanisms and more particularly to an improved bolting and opening mechanism for use on doors in areas such as on loading docks or in service corridors where they are subject to heavy use and impact damage.
2. Description of the Prior Art
Doors used in service corridors, on loading docks and other high use service areas are generally of rugged construction to resist damage from repeated impact with service carts, hand trucks, and the like. Typically such doors are of hollow steel construction and are mounted in pairs to provide minimum obstruction to traffic, but frequently are not classified as fire doors which require the conventional panic bar actuator extending across the width of the door for releasing the door latch in order to meet fire codes. Nevertheless, it is conventional to use latch bolts at the top and bottom of the doors, with the latch bolts being operated by vertical actuating rods which, in turn, are actuated by horizontally extending panic bars. The known panic bar actuated latch bolt mechanisms, or door hardware, is not only relatively expensive to manufacture and to install, but is particularly difficult and expensive to maintain.
Because of the difficulty in repairing the prior art service door hardware, it is common practice to simply remove and replace the hardware when it is damaged to the extent that it is no longer functional. Accordingly, it is a primary object of the present invention to provide an improved latch bolt mechanism for security doors which is highly reliable in operation and economical to produce.
Another object of the invention is to provide such a latch bolt actuating mechanism which is highly resistant to damage by impact with service carts, hand trucks and the like.
Another object is to provide such a latch bolt actuating mechanism which is readily accessible and easily and economically maintained.
In the attainment of the foregoing and other objects and advantages of the invention, an important feature resides in providing a latch bolt actuator which can be mounted onto the flat interior surface of a metal door using conventional fasteners such as self-tapping metal screws. A rigid metal housing is mounted directly onto the face of the door, or a reinforcing plate mounted on the door, adjacent the strike style, and an actuation lever is pivotally mounted within the housing for movement about a horizontal axis defined by a removable bolt or shaft. An actuator lever or paddle extends from the housing in position to be depressed toward the door face about the pivotal shaft to actuate the latch bolt, and the rigid housing includes stop means extending beneath the lever in position to engage and stop its movement after a predetermined rotation about the pivotal shaft whereby excess force on the lever is absorbed by the housing and transferred directly to the door without applying excessive stress to the actuating mechanism. The pivoted actuator is connected to a flexible metal strap which extends along the surface of the door and is connected to a conventional latch bolt supported in a guide mounted at the top edge of the door in position to engage a fixed keeper on the top frame or soffit of the door. A spring biased lost motion means is provided in the latch bolt and a cam surface on the latch is positioned to engage the keeper to permit the door to be closed and latched without actuation of the lever. Resilient biasing means is provided in the actuator housing to urge the actuator to the raised position to normally retain the latch bolt in position to engage the keeper when the door is closed.